Join thousands of gardeners across the UK who use our free service to buy, sell and swap plants ... and much more.

What is a Sage?

What is a Sage? | Copyright GreenPlantSwap Ltd

The Sage most know and use - Salvia officinalis

Hear the word 'Sage' and, it's more than likely, sage and onion stuffing will spring to mind. Sage is one of our best-known culinary herbs, and has been used in folk medicine since time immemorial, not to mention being part of the chorus of the folk song “Scarborough Fair”, along with parsley, rosemary and thyme. Common Sage has many names, including Dalmatian sage, Kitchen sage, True sage and Culinary sage.

The plant itself is a short-lived evergreen sub-shrub, which means that it keeps its leaves over the winter, and it rarely gets to more than waist-height, but can have thick, woody stems. Being a Mediterranean plant, it likes a well-drained soil, and likes to bask in the full sun where the bees can find it, and where the heat can bring out the familiar scent.

The botanical name for our cooking Sage is Salvia officinalis: the species name “officinalis” indicates a plant that was regularly used in cooking or medicine – it was, if you like, the “official” species.

Oddly enough, it can be toxic if you eat too much of it – the list of symptoms of over-indulgence include such delights as restlessness, vomiting, vertigo, tremors, and seizures. Luckily, we are not likely to eat ourselves into illness, as Sage is not at all palatable when it is raw, and in cooking it has a very strong flavour which can easily overwhelm the other ingredients, hence its time-honoured association with the equally strongly-flavoured onion.

Why is it called Sage?
The common name could be derived from the Latin salveo, meaning "to heal," or salvus, meaning "safe," or even salvare, meaning "to save" – no-one is quite sure, but as this herb has been used to treat ailments from consumption, ulcers, and snake bites, to plague, sores and (in tea form) colds and coughs, they are all equally likely.

Apparently the botanical name “Salvia” is occasionally used as a girl's name in Germany and Italy in the form Salvina, meaning “wise”, which is consistent with the English definition of the word “sage” i.e. having wisdom that comes with experience. Tough call for a newly named baby, but there you go.

So does eating sage make you wise? Well, recent studies have shown that a preparation of the essential oils of sage can indeed help with cognitive function, for people with Alzheimer's: however, the results are comparable to the effect of the amount of caffeine found in a cup of coffee, which may be easier and tastier. It seems unlikely that Sage will ever become more than a pleasant addition to our roast dinners.

What is Sage used for?
Medicinally, Sage has been recommended at one time or another for virtually every ailment, but in modern times its main use is culinary, or outdoors as a decorative plant.

In cooking, the most popular use of Sage is to go with onion for stuffing: there are a few adventurous recipes which suggest frying small strips of the leaves in butter to be used as a dressing on mashed root vegetables, or frying chopped sage leaves with onion then kneading them into a bread mix to make flavoured rolls – but Sage is a rather strong flavour, which makes it of limited use in general cookery.

In the garden it is far more versatile, as you can plant it in the herb garden, you can pop it in a decorative pot for year-round greenery, you can use it for low hedging, or to act as an evergreen statement in the middle of a mixed border, or as the foundation of a nectar bar, as bees love the pretty blue-lilac flowers, which are held on stiff upright stems from late spring right the way through summer.

Salvia officinalis "icterina'True Sages vary in colour. This is Salvia officinalis ‘Icterina’ - aromatic, pale green leaves with mottled yellow borders.

And best of all, it comes in different colours! As well as the usual silvery-green leaf, you could try Purple Sage, Salvia officinalis 'Purpurascens', with rich dusky purple foliage: there are several green-and-gold versions, including Golden Sage (Salvia officinalis 'Aurea') and Salvia officinalis 'Icterina': there is even one with multi-coloured green, white and purple-tinged leaves, called Salvia officinalis 'Tricolor'.

How do you maintain a Sage plant?
As with all kitchen garden herbs, the key factor in maintaining these plants is to cut them back regularly: the best, tenderest and tastiest leaves are the newest ones, and to promote new leaves, all you have to do is regularly pick them: this forces the plant to put on a spurt of growth and provide you with even more fresh new leaves.

Unfortunately, few of us use Sage more than “now and again”, and it is a vigorous grower, so most Sage plants become tough, woody things, flopping over under their own weight - unlovely to behold and a nuisance to walk past. A firm hand is required! Luckily, Sage is one of those benevolent plants that can tolerate being cut back very hard, and will happily form new leaves on old wood, so if your Sage gets away from you, all you have to do is cut about 50% of it down to a few inches high, wait for the new leaves to form, then cut down the other side to match. This is best done in spring and summer, when the plant is growing strongly.

Because of the speedy and sprawling growth, it is often better to exclude it from the herb bed, especially if space is at a premium, and to grow it as a specimen plant in a pot, or as a low hedge: all you have to do it trim it back hard after flowering, once a year, and you can easily establish a fragrant knee-high hedge which attracts bees all the day long.

Salvia officinalis is not a long-lived plant, partly due to its propensity to grow so large that branches fall outwards and break: also, a hard winter can cause it significant damage. Luckily, it is extremely easy to propagate from softwood cuttings, which can be taken at any time from spring to late summer. Just cut off the top 6“ (15cm) of some strongly-growing non-flowering shoots, remove all but the very top-most leaves, and push the bare stems into a pot filled with potting compost: you can put four or five cuttings into each pot. Water well, and leave aside until they have rooted. Checking underneath the pot can tell you when they are ready – if there are fine white roots peeping out of the bottom of the pot, it is time to plant them out!

How do you recognise the true Sage?
Salvia are part of the Labiatae family, commonly and inelegantly known as 'deadnettles', as some of them look like nettles but don't have any sort of sting. They all have square stems, which you can see for yourself if you cut them across – or if you try to roll them in your fingers, you can feel the corners juddering instead of rolling smoothly.

The leaves are so hairy that they are almost furry, or woolly, and this gives them a silvery appearance, even when they are variegated. Hairy leaves are typical of Mediterranean plants: the hairs prevent the plant from losing too much water by evaporation (technically, this process, in plants, is called transpiration), helping such plants to endure periods of drought without wilting.

Salvia argenteo photoLeaves on one of the hairiest, or 'woolliest' Sages, Salvia argenteo. Like other Mediterranean plants all Salvias, to varying degrees, have hairy leaves to reduce water evaporation.

Salvia leaves are held in opposite pairs up the stems, and each pair is at right angles to the next pair: in botanical terms this is called decussate. Each leaf has a long petiole (stalk) and is oval in shape, with a softly rounded tip: the leaf margins have small, blunt teeth. All parts of the plant - stem, petiole and leaf - are covered in short white hairs, giving the plant a silvery appearance, and giving it that slightly furry texture.

At flowering time, each stem elongates into a long upright spike of individual flowers, usually of blue-lilac, which are held high above the foliage.

What about all the other Sages?
Put the word Sage into the GreenPlantSwap Plant Finder and there are 119 plant records across 7 different genera which variously use the word 'Sage': Artemesia, Eranthemum, Perovskia, Phlomis, Pulmonaria ,Salvia and Teucriam. Sage is not just a common name, it's a common word liberally used it seems to describe plants with similar physical similarities to the 'official' Sage (e.g. Sage-leaved), because of their herbal, aromatic or medicinal use or because of their colour (silver-grey, Sage green).

Russian sage
For example, Perovskia atriplicifolia (Russian sage) is neither from Russia, nor part of the genus Salvia, but it is quite closely related, and shares the square stems, and the grey-green leaves. These leaves are mildly aromatic, the scent being variously described as sage-like, lavender-like, or smelling of turpentine. Sometimes, scent is in the nose of the beholder.

Like Salvia officinalis, it has been used medicinally in the past, but in modern times is cultivated solely for its attractive, lavender-like flowers which appear in June and can continue flowering right through into October, making it a late-season feast for bees.

Phlomis russeliana photoSticky Jerusalem sage (Phlomis russeliana) - striking architectural plants with opposite paired silvery-green leaves, but not true Sages.

Jerusalem sage
Phlomis fruticosa (Jerusalem sage) and Phlomis russeliana (Sticky Jerusalem sage), are also superficially similar plants: they have silvery-green leaves, but grow much taller, up to 1.5m, and have very distinctive bright yellow flowers which grow in whorls around the flowering stems, looking like pom-poms on a stick. These are striking architectural plants that will distinguish any border ... both in summer when in leaf and flower, and in autumn as stately silhouettes.

But they only share a name with our Sage, and a faint scent: the leaves are usually sessile (stalkless) or on very short stalks, making it easy to tell these two apart even if they are not flowering, which is a good thing as Phlomis is not edible, and in fact many people are allergic to it, which shows the importance of referring to plants by their correct, botanical, name!

And just to emphasise the point there is a different plant altogether that gets called Jerusalem sage, the lungwort Pulmonaria, which has oval, lance-shape green leaves and blue flowers. Despite the name, there is no mistaking plants in this genus for Phlomis or Salvia.

Wood sage
Teucrium scorodonia (Wood sage) earns its name because it has the same square stems and opposite greyish green Sage-like, lightly hairy leaves. This European woodland plant to 50cm, also known as the Wood germander, has wide medicinal uses.

Sage brush
Artemisia californica (California sagebrush) is one of dozens of woody, herbaceous 'Sage brush' shrubs with silver-grey aromatic foliage native to the Great Basin in the American North West. Known as Wormwood in the UK, Artemisia are a fine example (if one were needed!) of how common names vary from country to country.

Salvia patens 'Cambridge Blue'The brilliant flowers of Salvia patens 'Cambridge Blue'.

Blue sage
Then there are Blue sages. Some Salvia are notable for their blue flowers, such as Salvia patens 'Cambridge Blue' and Salvia 'Blue Angel' and Salvia officinalis itself. So the common name Blue sage is sometimes used for these. However, they are not to be confused with the unrelated Eranthemum pulchellum (Blue sage), which is popular in India and other parts of the tropics, and goes by the same name. This sprawling shrub to 1m has simple opposite, smooth edged leaves and delightful gentian blue flowers. It can be successfully grown in an English greenhouse, but don't mix it with onions for the Sunday roast!

Was this article helpful?
Tell us what you think/read other comments

Back to top
Production v5.2.0 (1129a0a)